Revert upstream changes triggering LB panic

[VenelinMartinov]

This reverts the following upstream PRs:
hashicorp/terraform-provider-aws#35671
hashicorp/terraform-provider-aws#35678
as a quick fix to mitigate #3421 until we root-cause it.

Details on my findings so far: #3421 (comment)
It looks to me like the issue originates somewhere in our handling of nulls/empty in the bridge, so seems unlikely to get fixed today.

It also adds a test for LB listeners. I've verified that the test triggers the panic without the patches and that the patches resolve it.

[github-actions]

Does the PR have any schema changes?

Does the PR have any schema changes?

Looking good! No breaking changes found.
No new resources/functions.

Maintainer note: consult the runbook for dealing with any breaking changes.

[t0yv0]

Does it still panic if this resource is opted into PlanResourceChange handling in here:

		shimv2.WithPlanResourceChange(func(s string) bool {
			switch s {
			case "aws_ssm_document", "aws_wafv2_web_acl":
				return true
			default:
				return false
			}
		}))

[VenelinMartinov]

Does it still panic if this resource is opted into PlanResourceChange handling in here:

Unfortunately that doesn't seem to fix it. I still get the panic with the following change there:

shimv2.WithPlanResourceChange(func(s string) bool {
	switch s {
	case "aws_ssm_document", "aws_wafv2_web_acl", "aws_alb_listener", "aws_lb_listener":
		return true
	default:
		return false
	}
}))

[t0yv0]

Lets make sure an issue (for the patch) remains open to get this root-caused. Let's ship the fix!

[VenelinMartinov]

I've opened #3427 to continue the investigation